When the results were published, the popular press joined the field of rejuvenation biotechnology in hailing the major preclinical advance: the tissue engineering of a live, beating rat heart, generated using a decellularized myocardium as a scaffold, onto which cardiac stem cells were seeded.((1); see video of recellularized myocardial construct with tracer illustrating region of motion). These results were quickly expanded by Taylor's group as well as by independent investigators, who within two years were not only reporting similar results with reseeded decellularized lungs(2,3) and liver,(4) but the transplantation and in vivo functionality (albeit for brief periods) of these constructs. And the most recent advance came at the end of last year, with the announcement from Shay Soker, Anthony Atala, and colleagues at the Wake Forest Institute for Regenerative Medicine that

Livers from different species [mice, rats, ferrets, rabbits, and pigs] were perfused with detergent to selectively remove the cellular components of the tissue while preserving the extracellular matrix components and the intact vascular network. The decellularized vascular network was able to withstand fluid flow that entered through a central inlet vessel, branched into an extensive capillary bed, and coalesced into a single outlet vessel. The vascular network was used to reseed the scaffolds with human fetal liver and endothelial cells. These cells engrafted in their putative native locations within the decellularized organ and displayed typical endothelial, hepatic, and biliary epithelial markers, thus creating a liver-like tissue in vitro.[our emphasis](5)

Dr. Taylor had let it be known to us that she was pursuing work with human research, using decellularized tissue donations for the biological scaffolds reseeded with human stem cells -- but we were not aware of just how quickly she was making progress.

"The hearts are growing and we hope they will show signs of beating within the next week," said Doris Taylor, a specialist in regenerative medicine at the University of Minnesota. "There are many hurdles to overcome to generate a fully functional heart, but the hope is that it may one day be possible to grow entire organs for transplant." ...

“There are many hurdles to overcome to generate a fully functional heart, but the hope is that it may one day be possible to grow entire organs for transplant.” [said Dr. Taylor] ...

Dr Taylor points out that there is no shortage of pigs from which to extract hearts if no human cadavers are available. Once such a heart has been stripped of pig cells and reseeded with human stem cells taken from a patient needing a new heart, there should be few rejections.

“We are a long way off creating a heart suitable for transplant, but the potential is clearly there," she said. ...

A key question for regenerative medicine researchers is how to make sure stem cells turn into the right thing - so they produce cardiac cells in the heart or liver cells in the liver.

Dr Taylor believes natural scaffolds help achieve this, partly because the stem cells recognise their shape. It may also be because they are each impregnated with chemicals specific to the organ from which they were derived. ...

“My ultimate goal is that one day we will be able to take a heart, probably from a pig, remove the cells and then replace them with cells grown from the patient's own body.

“Then we would build a heart to match the patient and transplant it into them. That's the dream.”